• Piyush Pathania

How Does Smart Defibrillator Diagnose The Sudden Cardiac Arrest?


In this digital age, we appear to have more alternatives for entertainment and recreation. Be that as it may, our hectic way of life and conflicting food habits have made us vulnerable to several diseases and some serious conditions like cardiac arrests. Gone are the days when individuals with just cholesterol and heart issues suffer from cardiac arrests. There are a few instances of Sudden Cardiac Arrests (SCAs) and millions of us appear to succumb to this without any health warnings. In such conditions, it is considered important to get the heart 'defibrillated' at the earliest opportunity – as the odds of endurance for the individual (experiencing SCA) decreases by 7 to 10% for every minute lost.

As we are living in this pandemic of COVID-19, more precautions are required for the cardiac patient as pre-existing cardiovascular disease and hypertension in addition to age and diabetes has emerged as fairly strong associations of a poor outcome in patients with this disease. Cardiovascular complications are frequent among COVID-19 patients and might contribute to adverse clinical events and mortality. Some people also have an emergency oxygen kit at home for coronavirus to deal with respiratory problems. The same is for cardiac patients where they are required to have a defibrillator at home which increases their chances of survival to maximum with fewer chances of infection.


What Is A Defibrillator?

A defibrillator is a device that restores a normal heartbeat by sending an electric pulse or shock to the heart. If the heartbeats unevenly or too fast or too slow, defibrillators are used to correct the heartbeat, but if the heart stops then these defibrillators can restore the electric pulse which works by using a moderately high voltage (200–1000 volts) by correcting the rhythm of the heartbeat. This disruption in the heart rhythm is called arrhythmia. Often there are no symptoms, but some people feel an irregular heartbeat which can be caused by damage from disease, injury, or genetics which might make them feel a little dizzy, fainted, and breathless.

Every defibrillator has its own working style and is used for different purposes. There are total 3 types of defibrillators :

  1. Automated External Defibrillator (AED)

  2. Implantable Cardioverter Defibrillator (ICD)

  3. Wearable Cardioverter Defibrillator (WCD)

How Do Defibrillators Work?


1. How Do AEDs Work?

AEDs are available in public places, which are used to save the life of people with sudden cardiac arrest in public places. AED can be used even by a bystander, which is used for emergencies while waiting for the ambulance to arrive. In such conditions, energy based AEDs are used, but there are other two types of AED:

  • Impedance-Based Defibrillators: It allows selection of the current applied based upon the transthoracic impedance (TTI). TTI is assessed from a test pulse and subsequently, the capacitor gets charged to the appropriate voltage.

  • Current-Based Defibrillators: It delivers a fixed dose of current, which results in defibrillation thresholds that are independent of TTI. The optimal current for ventricular defibrillation has to be 30 to 40 amperes independently of both TTI and body weight, thus achieving defibrillation with considerably less energy than the conventional energy-based method.

AED Architecture


AEDs need a processor with an associated operating system that is powerful enough to process and interpret several parameters at once, getting accurate results with a user-friendly interface.

Key Considerations For The Design:

  • Reliability and safety

  • Accuracy

  • Extremely fast boot times

  • Outstanding power management

  • Communication flexibility (wired and wireless)

  • Security

  • Rich and easy-to-use HMI

These design considerations make us contemplate which processor and software to use in the defibrillator. The single important objective is to seek out the supplier with a strong board support package (BSP).


In the past, medical device design first chose the processor and then the hardware design was made around that. Now, many companies are combining hardware and software designers, whereas a team considers a design platform composed of both hardware and software. Today, organizations and leaders understand the relationship between hardware and software that will run on it. It is wise to start by selecting a hardware and software reference platform that comes complete with a board support package (BSP) inclusive of an application-appropriate operating system and the necessary drivers to complete the work. In this way, design organizations can focus their energy on intellectual property rather than becoming an operating system or software company themselves.


2. How Do Implantable Cardioverter Defibrillators (ICDs) Work?

It is a device that is placed under the chest or abdomen which is connected to the heart using electrodes. The ICD is programmed in such a way that if it detects an irregular heartbeat, it instantly sends low/high electric shock to the person as per the need. The ICD also records the heart's electrical activity and heart rhythms, which is then used to program the ICD for irregular heartbeats.

3. How Do Wearable Cardioverter Defibrillators (WCDs) Work?

It is a device that is placed outside the body. The device has a belt that is connected with wires which is linked with the vest to monitor the heartbeat and if the rhythm is not correct it beeps to indicate an electric shock. If the person does not need a shock then he/she can turn off the alert, but if the alert is not responded to, then the device gives an electric shock to correct the rhythm.


Patent Analysis


1. Top 10 Countries

This chart describes the smart defibrillator patent strength in key regions across the globe. The chart covers the top 10 countries with the US leading the race with 2,676 patents in the defibrillator domain followed by WIPO with 1,375 patents. India (144), and Austria (88) accounted for the lowest number of patents in the industry across the globe.


2. Top 10 Players

The above chart depicts the total number of defibrillator patents assigned to the top market players. With 606 patents, Medtronic, Inc. is the top player. Pacesetter, Inc., Cardiac Pacemakers Incorporation and Zoll Medical Corporation are not so closely behind with 528, 465 and 95 patents respectively. Physio Control has the lowest number of patents among all with 35 patents.


Seminal Patent


Assignee: Zoll Medical Corp

Grant Date: 2015-03-27



The patent US10610679B2 states that the devices and methods described below provide for identification of ECG electrodes being handled by a rescuer, followed by prompts indicating which electrode the rescuer has in hand and prompts indicating the proper placement of that electrode. To detect the electrode being manipulated by the rescuer, motion sensors (accelerometers or other sensors) are mounted on the electrodes. (The system already knows which electrode is which, because each electrode is connected to a conductor cable which in turn is connected to a connector with unique inputs for each electrode). The system of the defibrillator to which the electrodes are connected is programmed (in addition to its programming for displaying and analyzing an ECG signal obtained through the electrodes, and generating and delivering a defibrillating shock to the electrodes or separate paddles), to analyze the sensor input to determine a characteristic of the motion of the electrodes, determine which electrode is being handled, and prompt the rescuer to put the electrode on the patient in its proper position. The prompts may be verbal prompts or images displayed on a display screen of the defibrillator.


Challenges And Future Developments


Cardiac patients have to face many challenges in real life, with different challenges for every defibrillator device. As AED devices are very effective in treating ventricular arrhythmias, it still needs a bystander capable of applying and operating it. On the other hand, the ICD device patients have to face device malfunction, fearing death during the shock, pain due to the shock, loss of control, cost of the device, and lifestyle limitations. Later, it was advocated that AED should be included in the compulsory safety equipment category such as smoke alarms or fire extinguishers, which increases the survival rate of the cardiac patient.


In the future, the defibrillator will be widely available to people in most areas and this may find a way to home, cars etc. In fact, various mobile phone apps will be created to let people know the nearest AED device and also get delivered with a drone. AED communication with bystanders will also improve with better video instructions and eventually live video feedback to help lay rescuers during the trickiest parts of administering AED-assisted CPR. AED will also offer better data sharing for communication outside the room and a more portable and lighter system.


References

  1. https://www.nhlbi.nih.gov/health-topics/defibrillators

  2. https://www.intechopen.com/books/cardiac-defibrillation/principles-of-external-defibrillators

  3. https://www.fda.gov/consumers/consumer-updates/how-aeds-public-places-can-restart-hearts#:~:text=The%20user%20 attaches%20two%20 sticky,and%20electric%20 shock%20is%20needed.

  4. https://patents.google.com/patent/US10610679B2/en?oq=US10610679B2

  5. https://www.medicaldesignandoutsourcing.com/theres-more-to-the-aed-than-meets-the-chest/

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